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Home >> Chevrolet >> 2006 >> Impala Police, 3.5 K >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.5L - DTC P0010 To DTC P0420 >> DTC P0420 >> Circuit/System Testing

Circuit/System Testing

NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice .
NOTE: Refer to Three-Way Catalytic Converter Damage Notice .
  1. With the engine in closed loop and at operating temperature, increase the engine speed to 1,500 RPM for 1 minute and then return to stabilized idle. Is the HO2S 2 voltage parameter as active as the HO2S 1 voltage parameter?
    • If it is as active then proceed with Circuit/System Testing.
  2. Inspect the catalytic converter for the following conditions:
    • Dents
    • A severe discoloration caused by excessive temperatures
    • Road damage
    • An internal rattle caused by damaged catalyst substrate
    • Restrictions
    • If a condition is found, then replace the catalytic converter.
  3. Inspect the exhaust system for the following conditions:
    • Leaks
    • Physical damage
    • Loose or missing hardware
    • Properly torqued HO2S
    • If a condition is found, then replace the exhaust system.
  4. Inspect the HO2S 2 for the following conditions:
    • Grounded wiring harness
    • Damage
    • If a condition is found then replace the HO2S 2.
    • If no physical condition is detected and the HO2S 2 is as active as the HO2S 1 after operating the engine at 1,500 RPM for 1 minute and then returning to a stabilized idle, then replace the catalytic converter.
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